For me, it is generally the simpler, faster, the better when it comes to throwing a wide, bottomless ring and then pulling up the side 4" (or so)...then slicing the ring into stand-up test pieces. But then again, I discovered the work of Gary Jackson from Chicago http://firewhenreadypottery.com/ who make his test tiles using the same stamps and textures that he uses on his production work...and to me, they are nice pieces of work in/of themselves.
I realize there is practical thought in Gary's approach, getting a much better idea of how his glazes will act...but I am seriously impressed with the quality, detail, and care that he takes.
Are you doing something different/creative with your test tiles? Is there a clay person you know who is knocking it out of the park when it comes to glaze testing ideas?
Test tiles by Gary Jackson: